The invention relates to improvements in methods of and in devices for attaching covering layers, such as decorative layers of leather, fabric or plastic sheet material, to supporting structures. The attaching devices or attachments of the present invention can be used with advantage to secure covering layers to complex supporting structures such as molded dashboards in motor vehicles, seats, chairs or armchairs and/or others.
In accordance with heretofore known proposals, covering layers are attached to complex supporting structures by means of an adhesive. A drawback of such proposals is that solvents which are contained in adhesives are likely to penetrate through the covering layer and affect the appearance of the object. Moreover, the adhesive is likely to age and to permit separation of the covering layer from the supporting structure. For example aging of many types of adhesives is promoted by exposure to sun. Still further, adhesives cannot be used in connection with many types of covering layer materials and/or supporting structures and/or when the covering layer does not directly overlie the supporting structure because it must conceal one or more layers of cushioning material. For example, it is customary and often required to pad the dashboards of motor vehicles so as to soften the impact in the event of an accident. Bonding of covering layers to relatively thick and/or relatively soft paddings necessitates the utilization of large quantities of adhesive which is likely to provide unsightly spots at the exposed side of the covering layer.
Proposals to avoid reliance on adhesives include the utilization of staples, rivets, screws and like fasteners which are likely to detract from the appearance of the finished object and must be concealed behind moldings and/or capping strips at the exposed sides of the covering layers. This contributes to the cost-and bulk of the objects, especially if the supporting structure has a complex outline with cavities bounded by concave surfaces and/or protuberances bounded by convex surfaces.